Preface for special issue on biofilm and c-di-GMP--Microbial society, c-di-GMP regulation, and new research techniques / 生物工程学报

Biofilm is prevalent in various ecological niches, in which microbial cells interconnect with each other through extracellular polymeric substances including polysaccharides, extracellular DNA, and proteins. When living in biofilms, the microbial cells employ small signalling chemicals as their "language" to communicate mutually, and exhibit remarkable differences in physiology compared to those living in planktonic state. It has been proven that the development of biofilm is subject to the regulation of c-di-GMP, an important second messenger found in prokaryotes. Given its important roles of biofilms in microbial infection, industry application, plant-microbe interactions and environmental pollustion, biofilm is one of frontier research areas in microbiology. This special issue of "Biofilm and c-di-GMP" systematically reviews the current progresses in the multiple research frontiers, including biotechnology, infectious diseases, environmental microbiology and plant pathology, with special focus on the methods and techniques in biofilm research. We hope that the issue will boost the interest of students and young scientists in this exciting area of microbiology.

Chemical agents modulating bacterial biofilm formation and development / 生物工程学报

Biofilm is a bacterial lifestyle ubiquitously in natural environments. Bacterial biofilm leads to drug resistance, a main reason why many infectious diseases are difficult to control. Due to the prominent points of biofilms implicated in infectious disease and the spread of multi-drug resistance, it is urgent to discover new antibacterial agents that can regulate biofilm formation and development. This review introduces chemical agents that could modulate bacterial biofilm formation and development.

Progress in c-di-GMP inhibitors / 生物工程学报

The cyclic dinucleotide c-di-GMP is known as an important second messenger in bacteria, which controls various important cellular processes, such as cell differentiation, biofilm formation and virulence factors production. It is extremely vital for the development of new antibacterial agents by virtue of blocking c-di-GMP signal conduction. Current research indicates that there are three potential targets for discovering new antibacterial agents based on c-di-GMP regulated signal pathway, which are c-di-GMP synthases, c-di-GMP degrading enzymes and c-di-GMP receptors. Herein, we review small molecules that have been developed to inhibit c-di-GMP related enzymes and indicate perspectives of c-di-GMP inhibitors.

The hierarchy quorum sensing network in Pseudomonas aeruginosa

Pseudomonas aeruginosa causes severe and persistent infections in immune compromised individuals and cystic fibrosis sufferers. The infection is hard to eradicate as P. aeruginosa has developed strong resistance to most conventional antibiotics. The problem is further compounded by the ability of the pathogen to form biofilm matrix, which provides bacterial cells a protected environment withstanding various stresses including antibiotics. Quorum sensing (QS), a cell density-based intercellular communication system, which plays a key role in regulation of the bacterial virulence and biofilm formation, could be a promising target for developing new strategies against P. aeruginosa infection. The QS network of P. aeruginosa is organized in a multi-layered hierarchy consisting of at least four interconnected signaling mechanisms. Evidence is accumulating that the QS regulatory network not only responds to bacterial population changes but also could react to environmental stress cues. This plasticity should be taken into consideration during exploration and development of anti-QS therapeutics.